Conventional switch devices operate to control the path on which a signal travels. In general, there are two basic types of switch devices in use: electromechanical and solid state. All switches are considered active devices, in that some sort of power supply is required in order to function properly. In electromechanical switches, a contact is provided that physically changes position during the switching process. Solid-state switches do not contain any moving parts and instead use some kind of semiconductor device for the switching process, which are basically either diodes or transistors. In general, diode switches sense current as a control input while switches comprised of transistors sense voltages as control inputs. One example of a transistor-based switch is comprised of a plurality of field effect transistors (FETs). FET switches are generally known to be utilized in connection with high frequency signal transmission, for example, radio frequency (RF).
In general, a FET switch is in an ON state (very low resistance) allowing any signal to pass from the drain to the source of the FET until a control voltage of a predefined amount (pinch-off voltage) is applied to the gate of the FET. When the pinch-off voltage is applied, the FET switches to an OFF state (very high resistance) and prevents any signal passing from the drain to the source of the FET. The advantage of FET switch is that the control voltage applied to the gate of the FET draws very little current, consuming no power in performing the switching function.
A major drawback of FET switches is that in the OFF state, a signal that one may desire to prevent from passing through the FET from the drain to the source applies a voltage at the drain of the FET. This voltage travels through the FET to the gate and adds to the control voltage input. As this voltage becomes greater than the control voltage, the OFF state FET begins to turn ON as shown in the FIG. 1a. 
In many of today's product designs, it is often desirable to require a lower control voltage for operation of a switch. For example, it may be beneficial to lower the control voltage of the switch having the exemplary characteristics of FIG. 1 from 5 volts to 2 volts while maintaining control over the same RF voltage. However, in order to reduce the control voltage of a switch, the RF voltage must be divided across additional FETs connected in series, as is shown in FIG. 1b. 
The configuration illustrated in FIG. 1b reduces the control voltage needed, but increases the resistance in the ON state. To overcome this added resistance, each FET is made larger and thus an increase in die size for the switch is required. This size increase, however, introduces many new problems in the switch, including:                1. The switch costs more, requiring more semiconductor material to manufacture.        2. The switch has poorer isolation, providing less resistance in the OFF state.        3. The switch has greater leakage in the control line, requiring more power to control the switch        
Accordingly, there is a need for an improved switch that can control a current output at lower control voltages, while providing the optimum balance of insertion loss, isolation, maximum power handling, harmonic generation suppression, and leakage current in the control signal.